With additional reporting on sidebars by Willie D. Jones, Elizabeth A. Bretz, and Chris Lang

21 August 2003—What was by most measures the biggest electricity outage in history, surpassing the blackouts in the western United States in the summer of 1996, swept northeastern and Great Lakes states and the Canadian province of Ontario late Thursday afternoon, 14 August. Long before power had been restored to businesses and residences from New York City to Cleveland, Detroit, and Toronto, politicians and commentators on both sides of the border were pointing fingers. But, in fact, major difficulties in the electric power system had been predicted by three U.S. Department of Energy (DOE) studies going back to 1998, and had been duly reported in the press (including IEEE Spectrum), with plenty of blame for inaction to go all around.

At this writing, it appears that the 2003 blackout started in facilities owned and operated by FirstEnergy Corp., a large utility headquartered in Akron, Ohio. Early in the afternoon of 14 August, one of its coal-fired power plants began to behave oddly and had to be taken off-line, or "tripped" in the industry parlance [see Timeline]. An hour later and perhaps coincidentally, at 3:06 p.m., Eastern Daylight Time, one of the company's major transmission lines failed. Inexplicably, the alarm system meant to warn the utility of such problems did not operate properly, and so FirstEnergy did not give regional regulators and organizations in adjacent states any warning of the mishap.

Over the next 45 minutes, three more transmission lines failed—two owned by FirstEnergy, the other by American Electric Power (Columbus), the other big Ohio utility—at 3:32, 3:41, and 3:46 p.m. By 4:30 p.m., most people in Ohio, Michigan, Ontario, New York State, New Jersey, and Connecticut were without power.

In the coming weeks and months, as regulators and power engineers sift through thousands of event records, the focus initially will be on what exactly the initiating events were, why failures propagated so rapidly through the northeastern grid, and why the grid system operators established to prevent such disasters were unable to deliver. Initially, responsbility for the inquiry was taken by the North American Electric Reliability Council (NERC, Princeton, N.J.), the self-regulating utility organization meant to improve the trustworthiness of the grid system, and it will continue to provide data and analysis. NERC's leaders have let it be known that an objective will be to determine whether key players failed to follow rules properly or whether the rules themselves were defective.

Ultimately, however, the issues raised by the blackout go far beyond that, which may be why DOE took charge of the inquriy on 20 August. For more than five years, NERC has sought and failed to get legislative authority to make its rules mandatory. During the same period, its U.S. government counterpart, the Federal Energy Regulatory Commission (FERC, Washington, D.C.), has been struggling to impose stronger regional oversight over grid operations—often encountering impassioned opposition from big utilities and their political allies. (FERC deals mainly with state and local governments, NERC with utilities.) Meanwhile, as growth in demand for electricity has outstripped additions to transmission capacity by a factor of two, the grid itself has come to be ever more thinly stretched.

The net result, as virtually all experts on the nation's grid system came to agree, was a disaster waiting to happen. "We all knew something like this was coming along," a leader in a 1999 DOE study of the transmission grid told IEEE Spectrum, on condition of anonymity. "We were all just waiting for the big one."

"Look," agreed Karl Stahlkopf, an executive at Hawaii Electric Co. (Honolulu) who previously managed power system research at the Electric Power Research Institute (Palo Alto), "everybody in the business knew something like this was going to happen. It wasn't a question of whether but when."